Instructional technologies for positioning a lower limb during muscular activity and detecting and tracking performance of a muscular activity

ABSTRACT

A soleus contraction measurement system includes a sensor configured to measure rotational movement when positioned on a user&#39;s foot with an X-axis oriented laterally across the user&#39;s foot, a Y-axis oriented parallel to the user&#39;s foot, a Z-axis orthogonal to the X-axis and the Y-axis, and a positive X-axis rotational movement corresponding to an increasing ankle angle, and a memory storing computer-executable instructions for controlling a processor to: measure an X-axis rotational movement, identify a positive X-axis rotational movement as a plantarflexion and a negative X-axis rotational movement as an ankle dorsiflexion, deem the plantarflexion a performed soleus contraction when the plantarflexion is immediately followed by the ankle dorsiflexion for two consecutive cycles of plantarflexion and ankle dorsiflexion, and cause performance information regarding the performed soleus contractions to be communicated.

TECHNICAL FIELD

This disclosure relates in general to the field of tracking physicalactivities, and more particularly, but not by way of limitation, toinstructing muscle activity and detecting, monitoring, and/or trackingsoleus contractions.

BACKGROUND

This section provides background information to facilitate a betterunderstanding of the various aspects of the disclosure. It should beunderstood that the statements in this section of this document are tobe read in this light, and not as admissions of prior art.

Health and fitness is an increasing concern as the population becomesmore sedentary. It has been recognized by the inventor thatplantarflexion movements performed in a specific fashion has heretoforeunrecognized health benefits. Teaching the proper form for thesemovements and implementing proper performance of these movements can bedifficult without trained staff and specialized, expensive equipment.There is a need and desire for devices and systems that can identifywhen the particular movements are being performed and to serve as amonitor and activity tracker.

SUMMARY

An exemplary soleus contraction measurement system includes a sensorconfigured to measure rotational movement when positioned on a user'sfoot with an X-axis oriented laterally across the user's foot, a Y-axisoriented parallel to the user's foot, a Z-axis orthogonal to the X-axisand the Y-axis, and a positive X-axis rotational movement correspondingto an increasing ankle angle, and a memory storing computer-executableinstructions for controlling a processor to: measure an X-axisrotational movement, identify a positive X-axis rotational movement as aplantarflexion and a negative X-axis rotational movement as an ankledorsiflexion, deem the plantarflexion a performed soleus contractionwhen the plantarflexion is immediately followed by the ankledorsiflexion for two consecutive cycles of plantarflexion and ankledorsiflexion, and cause performance information regarding the performedsoleus contractions to be communicated.

An exemplary contraction system includes a sensor configured to measurerotational movement when positioned on a user's foot with an X-axisoriented laterally across the user's foot, a Y-axis oriented parallel tothe user's foot, a Z-axis orthogonal to the X-axis and the Y-axis, and apositive X-axis rotational movement corresponding to an increasing ankleangle, a memory storing computer-executable instructions for controllinga processor to: measure an X-axis rotational movement, identify apositive X-axis rotational movement as a plantarflexion and a negativeX-axis rotational movement as an ankle dorsiflexion, deem theplantarflexion a performed soleus contraction when the plantarflexion isimmediately followed by the ankle dorsiflexion, and cause performanceinformation regarding the performed soleus contractions to becommunicated; and a base having a bottom surface extending along ahorizontal plane, a placement surface for locating the user's foot, anda communication device configured to communicate the performanceinformation.

An exemplary method operable by a processor of a measurement unit formonitoring plantarflexions includes measuring, with a sensor located ona user's foot, rotational movement about an X-axis, where the X-axisextends laterally across the user's foot, a Y-axis extends parallel tothe user's foot, a Z-axis extends orthogonal to the X-axis and theY-axis, and a positive X-axis rotational movement corresponds to anincreasing ankle angle; identifying a positive X-axis rotationalmovement as a plantarflexion and a negative X-axis rotational movementas an ankle dorsiflexion; deeming the plantarflexion a performed soleuscontraction when the plantarflexion is immediately followed by the ankledorsiflexion for two consecutive cycles of plantarflexion and ankledorsiflexion; and causing performance information regarding theperformed soleus contractions to be communicated.

This summary is provided to introduce a selection of concepts that arefurther described below in the detailed description. This summary is notintended to identify key or essential features of the claimed subjectmatter, nor is it intended to be used as an aid in limiting the scope ofclaimed subject matter.

BRIEF DESCRIPTION OF THE DRAWINGS

The disclosure is best understood from the following detaileddescription when read with the accompanying figures. It is emphasizedthat, in accordance with standard practice in the industry, variousfeatures are not drawn to scale. In fact, the dimensions of variousfeatures may be arbitrarily increased or reduced for clarity ofdiscussion. As will be understood by those skilled in the art with thebenefit of this disclosure, elements and arrangements of the variousfigures can be used together and in configurations not specificallyillustrated without departing from the scope of this disclosure.

FIG. 1 illustrates an exemplary measurement and tracking system unitaccording to one or more aspects of the disclosure.

FIG. 2 illustrates a triaxial sensor and a three-axis frame ofreference.

FIG. 3 schematically illustrates exemplary sensor locations on a user.

FIG. 4A schematically illustrates performance of an exemplary soleuscontraction from a starting ankle angle to an ending ankle angle with a“good” soleus electromyography signal.

FIG. 4B schematically illustrates performance of an exemplary soleuscontraction from a starting ankle angle to an ending ankle angle with a“poor” soleus electromyography signal.

FIG. 4C schematically illustrates performance of an exemplary soleuscontraction with the user's foot on a base station from a starting ankleangle to an ending ankle angle with a “good” soleus electromyographysignal.

FIG. 5 graphically illustrates goniometer determined range of motionversus a gyroscope determined range of motion for a single gyroscopelocated on a user's foot.

FIG. 6A graphically illustrates exemplary rotational movement of auser's foot, as measured by a triaxial sensor located on the user'sfoot, when walking.

FIG. 6B graphically illustrates exemplary rotational movement of auser's foot, as measured by a triaxial sensor located on the user'sfoot, when performing ankle extensions deemed soleus contractions.

FIG. 7A graphically illustrates exemplary rotational movement about anX-axis extending laterally relative to a user's foot caused by walking.

FIG. 7B graphically illustrates exemplary rotational movement about anX-axis extending laterally relative to a user's foot that are deemedsoleus contractions.

FIG. 8 illustrates an exemplary method, operable by a processor of ameasurement unit, for monitoring plantarflexions.

FIG. 9 illustrates an exemplary measurement and tracking system unitincorporating a base foot placement according to one or more aspects ofthe disclosure.

DETAILED DESCRIPTION

It is to be understood that the following disclosure provides manydifferent embodiments, or examples, for implementing different featuresof various illustrative embodiments. Specific examples of components andarrangements are described below to simplify the disclosure. These are,of course, merely examples and are not intended to be limiting. Forexample, a figure may illustrate an exemplary embodiment with multiplefeatures or combinations of features that are not required in one ormore other embodiments and thus a figure may disclose one or moreembodiments that have fewer features or a different combination offeatures than the illustrated embodiment. Embodiments may include somebut not all the features illustrated in a figure and some embodimentsmay combine features illustrated in one figure with features illustratedin another figure. Therefore, combinations of features disclosed in thefollowing detailed description may not be necessary to practice theteachings in the broadest sense and are instead merely to describeparticularly representative examples. In addition, the disclosure mayrepeat reference numerals and/or letters in the various examples. Thisrepetition is for the purpose of simplicity and clarity and does notitself dictate a relationship between the various embodiments and/orconfigurations discussed.

The term “soleus push-up” (SPU) is used to denote a specific type ofplantarflexion with a relatively high soleus electromyography (EMG)on-time (i.e., soleus activation) coinciding with upward angular motionof the ankle. Through unexpected experimental results, the inventor hasdeveloped novel methods of performing soleus contractions to achievebeneficial health effects. This method of soleus contraction and theresultant health effects have not heretofore been studied. In thestudies and experiments the inventor used several types of expensivelaboratory grade equipment not readily available for most clinicians,therapists, and laypersons. It is important to provide systems that arerelatively inexpensive and easy to use, in order for the public tobenefit widely from learning how to perform these novel soleuscontractions. There are unique aspects of learning and tracking thissmall and low effort movement that utilize innovations disclosed herein.

These novel soleus contractions are a potent physiological method toenhance systemic lipid and glucose metabolism. Disclosed is ameasurement unit with a wearable sensor, e.g., a gyroscope, that can beattached to the user's foot for quantitative monitoring of soleuscontractions throughout the day in free-living conditions. The systemsand methods can be used for instructing proper performance of soleuscontractions and tracking these soleus contractions for the purpose ofpreventing and/or treating human metabolic and cardiovascular conditionsresponsive to soleus muscle contractions. The measurement unit can beused for identifying proper performance of a soleus contraction, forexample to train a user in the proper position of the lower leg and footand the proper movement, as well as tracking the performance of soleuscontractions and distinguishing movements that qualify as the desiredsoleus contractions from other miscellaneous lower limb movements andvibrations including, without limitation, walking, tapping a foot, andriding in a vehicle. The measurement unit may distinguish between soleuscontractions performed when standing and when sitting. Benefits of thesoleus contractions are achieved in novel ways not associated withtypical exercises. For example, effective soleus contractions can beachieved at lower rates (contractions/min) than at higher ratesperformed with the same range of motion (ROM). Additionally, effectivesoleus contractions are performed when seated and without addingresistance to the movement.

Prior to this disclosure, skilled practitioners did not have knowledgeof these novel soleus contractions nor a reason to develop or constructsoleus contraction measurement and monitoring systems and methods. Thisknowledge includes the ability to know what human movements to excludefrom tracking. Plantarflexion is a general term of the process of anklebending caused by contraction of the calf musculature. The inventor hasidentified that there are specific biomechanical parameters during onespecific type of plantarflexion, that the inventor has developed, toisolate the soleus muscle from other muscles, which is remarkablysuperior in activating the soleus to a higher level than other types ofplantarflexion such as walking. Surprisingly, it also provides anindefatigable method of sustaining human metabolism for prolongedperiods when sitting comfortably. There are specific biomechanicalparameters for how the soleus contractions can induce an intensemetabolic stimulus during an SPU, unlike other types of plantarflexionthat have previously been studied. Finally, there is knowledge regardinghow to avoid misclassifying non-specific movement, e.g., car riding andwalking, from the specific SPU movement and soleus contraction.

These soleus contractions can be performed when sitting. One reasonthere are physiological health gains by unique biochemical processeswith this kind of treatment is because people can accomplish the SPUcontractions frequently throughout the day. People sit on average ˜10hours/day, even more so in people at risk for chronic diseases impactedby muscular inactivity. The inventor has shown the real-world behavioralapplicability and adaptive health benefits after one has been taughtthis behavior. A diverse group of adult participants voluntarilyperformed SPU contractions during normal daily sitting an averageduration close to half of their total daily sitting time (5.3±0.4hours/day, or ˜35 hrs/week; N=32). That is remarkable compared to anyother kind of physical activity. It is made possible by the ease of use,safety, and the fact the soleus muscle is indefatigable with thisparticular activity. The inventive systems and methods described hereinwill be essential for people to identify and track proper performanceand the cumulative time proper soleus contractions are performed becausepeople sit on average about 50-55 times per day and have little memoryof each of those periods. The only way to make it feasible and accuratefor people in the real world to track the quality of the SPUcontractions and the magnitude of expected benefits is with the systemsand methods disclosed herein.

Means to avoid errors in accurately capturing performed SPUs aredisclosed based on problems and solutions identified by a large amountof empirical experimentation. One major source of error with activitytrackers includes car riding, because it is a common behavior thatinvolves sitting for long durations and car riding involves a highamount of vibration even on smooth roads. With only the use ofaccelerometers, which are more commonly used to track physical activityin general, it has been found that a high amount of error is introducedin discerning between SPU contractions and this non-specific vibration.A second problem solved was that with a gyroscope, the ROM overlapsbetween SPU contractions and car riding. This problem was solved byanalysis of the duration and ROM of each singular movement todistinguish between non-specific movements and SPU contractions. Cardriving causes many movements with a duration typically less than about50 ms versus a duration greater than about 80 to 100 ms for the upstrokeof even the high velocity SPU contractions.

The disclosed systems and methods can be used by clinicians to instructpatients how to perform SPU contractions, by non-experts to learn ontheir own how to perform proper SPU contractions, and to track daily SPUcontractions. An advantage of using a gyroscope and possibly anaccelerometer is that they are inexpensive and commonly available.Gyroscopes and accelerometers are mass produced and included with amagnetometer in what is known as an inertial measurement unit (IMU). Forpurposes herein, a measurement unit, or IMU, may include only agyroscope or utilize only the gyroscope. Because an SPU contraction is anovel movement, no one previously has envisioned how a gyroscope can beused for the specific purpose of teaching and tracking this specific andunique type of soleus contraction. Typically, physical activity trackersuse accelerometry and focus on measuring things like steps or total bodyacceleration. On the other end of the continuum, high end research gradeequipment like electronic goniometers, electromyography, and indirectcalorimetry are fragile and expensive. Devices described herein are moreuseful than that in a clinical setting and by the end users in thepublic. It is useful to teach the movement and to provide the user withimmediate feedback, and daily summaries from an app on a phone orcomputer, for example of the position of the ankle and ROM of the anklewhen sitting. One of the specific novel and practical aspects of thetechnologies is that instead of having to wear a pair of gyroscopes ontwo body parts to monitor the ROM of a joint, as is standard inbiomechanics research, it is possible to only have to wear a singlesensor, or sensor unit, to detect and measure SPU soleus contractions,if placed properly on the foot and using it as disclosed herein.Furthermore, by knowing the exact duration of each individual SPUmovement and the velocity during a given ROM, e.g., 250 msec upstroke ata velocity of 180 deg/sec during a 45-degree ROM, the sensitivity andspecificity can be high enough to discern the magnitude of intendedbenefits, while also avoiding artifact movements that take place duringother human movements like walking, fidgeting, and car riding. This workinvolves distinguishing SPU soleus contractions from other types ofmovement, e.g., walking and car driving, in order to achieve a highlevel of specificity. Measurement units have sufficient samplingfrequency and battery technology to be adapted for the novel purposesintended. If the measurement unit includes a magnetometer, themagnetometer may be turned off to save battery life. The software can,with the specific velocity of ankle movement, the duration, and/or ROMof each SPU movement, teach and track the SPU contractile activity.

In developing the SPU contraction, the inventor was originally thinkingmostly about specific disease conditions closely related to muscularinactivity in the lower limb. For one, PAD (peripheral artery disease)is a vascular disease with a low rate of blood flowing through thearteries perfusing the legs. PAD can be painful and especiallysymptomatic in the calf musculature of the lower part of the legs, wherethe soleus is the predominant muscle. A second increasingly common,because of an aging and obese population, and often debilitating andpainful condition like PAD is swelling in the lower legs and feet. Legswelling/edema is a common disorder but difficult to treat. Neither PADor edema are effectively treated with medications or surgeries as withother cardiovascular conditions. However, soleus muscle contractions arethe most effective means to increase blood flow to the lower legs. Also,the soleus muscle pump is an effective mechanism to redistribute tissuefluid back to the heart and out of the limbs. Therefore, it is believedthat the disclosed systems and method will be of great usefulness forthese disorders. SPU contractions are the most comfortable andphysiologically powerful type of soleus muscle contraction studiedheretofore, and results show it can safely be taught and trackedquantitatively.

As described herein, the soleus muscle contractions have an especiallyimportant role in blood flow because the soleus has a phenotypedifferent from other muscles such that it has the greatest capacity forflow of all muscles in the lower limb, and by being the most distalmuscle away from the heart, it is the most important muscle for pumpingon the veins to return fluid back to the heart and prevent leg/footswelling in addition to vein disorders in the legs. The rate of bloodflow in the leg is directly dependent on the metabolic rate of thesoleus muscle. The rate of blood flow is elevated during walking, butthere is now strong evidence that the increase in blood flow and muscleoxygen consumption is markedly greater during SPU contractions than whenwalking. In fact, it is calculated that the oxygen consumption by theSPU contractions is almost 10-fold greater in the recruited muscle massthan when walking. Secondly, because the SPU contractions do not inducefatigue, joint pain, and can be safely graded incrementally with thesystems and methods disclosed herein, the SPU contractions will be aneffective means for patients with PAD to titrate the stimulus of soleusmetabolism to give an optimal magnitude of health benefit without thetypical pain associated with walking. Finally, and related to this lastpoint, the duration of SPU contractions is markedly greater than one ispractically able to do with walking because most people sit 10 hours perday and SPU contractions can be done while sitting. Therefore, there isan abundant opportunity for patients to adhere to prescriptions fordaily dosing of SPU contractions to improve their health.

The inventor's physiological and biochemical research has focused, inlarge part, on impaired glucose tolerance (IGT) and hyperinsulinemia inthe postprandial period. IGT is the strongest metabolic risk factor fordeveloping type 2 diabetes. IGT is often described as the most importantclinical biochemical parameter determining health outcomes related toglucose disorders, Alzheimer's disease, some cancers, neuropathies,dyslipidemia, and cardiovascular conditions. It is also one of the mostdifficult risk factors to improve by medications or lifestyleapproaches. However, the inventor has shown with SPU contractions therewas on average about a 50 percent reduction in the postprandial glucoseexcursion in highly controlled laboratory studies. The research alsodemonstrated that the insulin concentration, which is not only involvedin diabetes risk, but numerous other conditions including some cancersand cardiovascular health, was reduced at least as much as the glucoseexcursions. The research identified that the VLDL (very low-densitylipoprotein) was markedly reduced in each individual tested within asingle day (acute) of SPU contractions. VLDL has much implication notonly for cardiovascular health, but also fat metabolism, liver health,and chronic inflammatory processes.

Notably, the research results describe a quantitative dose-responsebetween the level of SPU contractions and the desired physiologicalresponse. Therefore, with the devices, systems, and methods describedherein, people will be able to gauge their level of SPU contractionsobjectively in relation to potential health benefits. Important to thisis the perception of effort expended during SPU contractions is notproportional to the dose of the SPU contractions, necessitating thesetechnologies for quantifying the SPU contractions and thereby providingthe user with feedback. Unlike most types of muscle contractions, e.g.,weightlifting or bicycling, people were unable to accurately assess therelative effort of SPU contractions by the normal mind-muscleperceptions of effort. Normally the metabolic stress put on the musclecan be felt and people use this as a gauge for progressing in theirexercise prescription. However, with SPUs, everyone finds it such a loweffort behavior, that they are unsure of whether they are doing itcorrectly to bring about the large metabolic responses noted above andhow to optimize the movement.

SPU contractions do not need external resistance, i.e., an unloadingmuscle contraction. This is only possible because of a specificbiomechanical movement that can be taught and monitored with thetechnologies disclosed herein. This reduces fatigue, adds to safety, butdoes not reduce the metabolic cost of the activity. In a fatigueevaluation, the soleus activation, from electromyography (EMG), can bematched between SPU contractions and other types of plantarflexion suchas standing heel lifts or sitting and doing plantarflexion againstexternal resistance (a loaded muscle contraction). In each individual,there was a marked difference in the effort to do SPU contractions andthe other types of plantarflexion commonly prescribed for exercise. Whenworking at a soleus EMG (held steady at ˜40% of EMGmax), standing heellifts and seated loaded SPU contractions induced fatigue in theseindividuals within two minutes. The perceived effort increased graduallyduring the 120 second to the point of being unbearable to continue. Incontrast, the SPU contractions were fatigue resistant such that theeffort was perceived as very light. Even when doing the SPUscontinuously immediately after the fatiguing types of plantarflexion,the SPU contractions were rated as a 1 on scale of 1-10, indicating lowrelative effort. Furthermore, over thirty individuals who were generallyunfit and untrained were tested. With the specific instructionsprovided, the test subjects were able to comfortably sustain SPUscontinuously for hours at a time without a sense of exertion or anyadverse responses such as muscle cramps or joint pains. The activity isnot stressful on the heart because the heartrate and blood pressureremain close to resting levels. This work was including subjects whooften had a history of cardiovascular disease and therefore is a safeway to induce increases in muscular blood flow and cardiac stroke volumein the absence of a significant increase in blood pressure and heartrate that would be seen with traditional exercise. Important to all ofthis, the subjects would not have been able to learn the SPUs ormaintain the SPU level without the feedback provided from knowledge ofthe range of motion and isolation of the soleus muscle contractions. Onthe contrary, when people were not provided with instructions for what ahigh-quality contraction is, people would often resort to a low-qualitySPU that would not produce an adequate soleus EMG nor provide a superiorincrease in oxygen consumption, fat metabolism, and carbohydratemetabolism.

The SPU contractions produced unexpectedly marked improvements in keyhealth related outcomes even in non-diseased healthy individuals.Because of this, widespread utilization of the devices, systems, andmethods described herein is anticipated for people seeking betteroverall health. This includes a consistent doubling in whole-body fatmetabolism throughout the entire day, a robust reduction in plasmaVLDL-triglyceride acutely within a single day, and improved glucosetolerance and less hyperinsulinemia acutely within a single day. Properperformance of the soleus contractions as taught herein lead to healthgains in otherwise normally healthy people. A study as identified howtwo months of performing SPU contractions voluntarily whenever theparticipants are sitting at work or at home led to reduced low gradesystemic inflammation, improved biomarkers of liver metabolism, improvedbiomarkers of atherosclerotic cardiovascular disease, improvedbiomarkers related to disruptions caused by cellular iron metabolism,improved glucose regulation, reduced plasma insulin, and improved fatmetabolism.

SPU contractions can be taught and monitored with the innovationsdescribed herein. This will provide a low-cost treatment to be used inmultiple common debilitating medical applications, as well as for peopleconcerned about improving their health to avoid disease.

FIG. 1 illustrates an exemplary soleus contraction measurement andmonitoring unit, generally denoted with the numeral 10. The unit mayinclude one or more separate components in operational communicationwith one another. Measurement unit 10 includes one or more sensors 12, aprocessor 14, a memory 16 storing computer-executable instructions 18for controlling the processor, a battery 20, a communication device 22(display and/or audible and/or tactile device), wireless transceiver 24,and a client and/or server 26. The instructions, or logic, 18 mayinclude soleus push-up identification logic 28, tracking logic 30, andwireless communication logic 32.

Sensor 12 may consist only of a gyroscope. Sensor 12 can include agyroscope and an accelerometer, which may be packaged together orconfigured for positioning in different locations from one another.Sensor 12 can be packaged as an inertial measurement unit (IMU) having agyroscope, accelerometer, and a magnetometer. At least one sensor, forexample the gyroscope is configured to be worn on a user's foot, forexample on the top of the foot or the bottom of the foot.

Performance information regarding movements, in particular performanceof particular soleus contractions, is communicated via communicationdevice 22 to the user. The information may be communicated visually,audibly, and/or tactilely. Communication devices 22 may be located indifferent locations from the sensor, for example on a separate wearabledevice from the sensor, or on a smart phone, tablet, computer, and/orbase station. In some embodiments, a base station includes acommunication device 22 to communicate performance information. Forexample, the communication device 22 may include a visual display. Insome examples, the base may include a tactile device that willcommunicate performance information via the user's foot, for example,that soleus contractions are being performed. An example of a tactilecommunication device includes a vibrating pad positioned at the user'sforefoot on the base.

One or more of the components of measurement unit 10 can be located withand/or separate from the sensor that is positioned on the user's foot.For example, the processor, memory, and logic can be located remote fromthe sensor. For example, a measurement unit portion including forexample the sensor, storage, and logic may be configured to be worn on auser's foot and be in communication, wirelessly or by wire, with aremote computing device and the internet. The remote computing devicecan support installation and execution of applications, such as activitytracking application that may be downloaded from a server. The remotedevice can be a smartphone, handheld computer, table computer, laptopcomputer, desktop computer, or other computing device interfacing withthe wearable sensor.

FIG. 2 illustrates an exemplary 3-axis inertial sensor 12, such as agyroscope. In an exemplary embodiment, the monitoring unit includes agyroscope to measure rotational movement. A triaxial gyroscope directlymeasures the angular velocity of rotation in 3 axes. From this, both theduration of each rotational movement and the range of motion (ROM) aredetermined with the measurement unit.

FIG. 3 schematically illustrates a user in an exemplary position forperforming the subject soleus contractions and exemplary positions forsensors of a measurement unit. A triaxial sensor 12, in the form of agyroscope, is worn on a foot 300 of a user 302 with the Y-axis alignedparallel to the foot from toe to heel, the X-axis extends laterally fromside to side across the foot, and the Z-axis is parallel with gravity.FIG. 3 illustrates user 302 sitting with the thigh 304 generallyparallel to the floor 315. When the X-axis is rotating, the back of thefoot and leg 306 (shin) are rising. This action is thereby measuringankle 310 extension, which is caused by the rotation of the ankle jointduring the subject soleus contraction. Sensor 12 is positioned on thetop or bottom of the foot, as opposed to the side of the foot, with theX-axis, as the primary axis of rotation, parallel to the floor andperpendicular to the sagittal plane or direction of gravity. When sensor12 includes both a triaxial gyroscope and triaxial accelerometer, suchas in a common inertial measurement unit, the position of sensor 12 canbe calibrated knowing the orientation with the gravitational field fromthe triaxial accelerometer output. The sensor may be arranged so thatX-axis rotational movements in a first direction, for example positivemeasurement outputs, correspond to an increasing ankle angle 316(plantarflexions) and the X-axis rotational movements in a seconddirection, for example negative measurement outputs, correspond to adecreasing ankle angle (dorsiflexion).

FIGS. 4A, 4B, and 4C schematically illustrate performance of SPUs withdifferent starting ankle angles 316 and performed with different rangesof motion resulting in different quality of soleus contractions asdetermined by soleus electromyography (EMG). The top view of each figureshows the start position of a soleus push-up, with heel 312 and forefoot314 down and in contact with a surface 315. It is desirable for thestarting ankle angle 316 to be in the range of about 60 to 80 degrees,depending on the user's flexibility, which facilitates a greater rangeof motion for each SPU contraction. Ankle angle 316 is the angle betweenfoot 300 and shin 306, for example, an ankle angle of 90 degrees isdefined as the tibia and sole of the foot at a right angle. The bottomview in each figure shows the ankle angle at the end of the ankleextension, after heel 312 has been raised relative to forefoot 314.FIGS. 4A and 4C illustrate soleus contractions with a good EMG signal.FIG. 4A illustrates user 302 in the seated position with the foot onfloor 315 and pulled back positioning the foot under the user andplacing ankle angle at 80 degrees. This position may be difficult toachieve due to the user's flexibility and/or the type of chair, sofa,couch, on which the user is sitting. FIG. 4B illustrates the user withthe legs extended out, in a more common seated position, and with thefoot flat on the floor placing the ankle angle at 110 degrees. With astarting ankle angle 316 of 110 degrees, the ROM of a plantarflexion islimited, resulting in poor soleus activation. FIG. 4C shows a user usinga base station 350 to achieve a beneficial starting ankle angle. Basestation 350 can be configured in different forms and arranged so thatthe user can place foot 300 on base 350 with the foot positioned forwardof the user's body to achieve a starting ankle angle 316 of betweenabout 60 to 80 degrees. For example, base 350 has a horizontal, planar,bottom surface 318 for resting on the floor and a placement surface 320extending upward from the bottom surface and configured for placement ofthe user's forefoot. In FIG. 4C, the placement surface is illustrated asa planar surface, however, it may be a curved surface, such as a base350 having a semi-circular shape. The placement surface is configuredfor placement of the user's forefoot on the placement surface asufficient distance above the floor 15 so that the user's heel can freefloat without being obstructed by the floor. In some configurations,base 350 may be planar, or substantially planar, for example with theplacement surface generally parallel to the floor. As further describedbelow, base 350 may include one or more mechanisms for conveyingperformance information to the user.

FIG. 5 graphically illustrates the accuracy of a single gyroscopepositioned on a foot in measuring the range of motion of the anklerelative to the range of motion measured with a goniometer. There ishigh agreement of the goniometer determined ROM and the ROM calculatedfrom a gyroscope of the top of the foot in the tested range of 8 to 33degrees ROM. The dotted line shows the line of unity which is on thetheoretical relationship between perfectly matching measures.

The measurement unit and system can distinguish a SPU contraction motionfrom other movements. A gyroscope worn on the user's foot, for exampleas illustrated in FIG. 3 , measures rotational movement of the footabout the ankle. FIGS. 6A, 6B, 7A, 7B graphically illustrate rotationalmovement outputs from a triaxial gyroscope positioned on a user's footwith the X-axis extending laterally, side to side, relative to the foot,the Y-axis extends parallel to the foot, heel to toe, and the Z-axisextends orthogonal to the X-axis and the Y-axis and parallel to gravity.The axes are oriented such that plantarflexions are identified bypositive X-axis rotational movements.

FIG. 6A graphically illustrates exemplary rotational movement of auser's foot about the X-axis, Y-axis, and Z-axis when walking. FIG. 6Bgraphically illustrates exemplary rotational movement of a user's footabout the X-axis, Y-axis, and Z-axis when performing ankle extensionsthat are deemed soleus contractions not produced by walking. FIGS. 7Aand 7B are expanded views of the X-axis rotational movement measurementsof FIGS. 6A and 6B.

During an SPU contraction, the X-axis rotational movement of the foot isthe primary axis of rotation, with relatively less motion about theY-axis and the Z-axis. As illustrated in FIG. 6B, neither the Y-axisrotational movement nor the Z-axis rotational movement exceed the X-axisrotational movement. For soleus contractions, the Y-axis and the Z-axisrotational movement do not approach the X-axis rotational movement.

The X-axis rotation of the ankle is the movement that causes the leg torise upward because of ankle extension (plantarflexion) and is indicatedby the positive X-axis rotational movement 502. Following this phase ofpositive, or first direction, rotational movement 502 is a negativerotational movement indicating that the leg is moving in the oppositedirection back downward (ankle dorsiflexion). With an SPU contraction,as measured by a gyroscope on the foot, there is a repeating pattern ofplantarflexion 502 (positive rotational movement) immediately followedby a period of ankle dorsiflexion 505 (negative rotational movement). Asignificant contrast with walking (when measured with a gyroscope on thefoot) is that in each stride there are two periods of plantarflexion 502without a negative rotational movement, or without a significantnegative rotational movement. Thus, a plantarflexion 502 can be excludedfrom being deemed a soleus contraction when the plantarflexion is notimmediately followed by an ankle dorsiflexion 505 for two consecutivecycles of plantarflexion and dorsiflexion. FIGS. 6A and 7A show an ankledorsiflexion 505 between adjacent plantarflexions 502, however, there isnot an ankle dorsiflexion immediately following each plantarflexion 502for two consecutive cycles of plantarflexion and dorsiflexion.

FIGS. 7A and 7B show the calculated ROM for plantarflexions 502 andankle dorsiflexions 505. The range of motion for each plantarflexion 502peak provides useful information about the rotational movement fordefining a soleus contraction. In FIG. 7B, there is a positive X-axisrotational movement equivalent to 33-34 degrees in consecutiveplantarflexion 502 peaks and an intervening ankle dorsiflexion 505,34-degree negative signal. The plantarflexion 502 is immediatelyfollowed by an ankle dorsiflexion 505 in two consecutive cycles ofplantarflexion and dorsiflexion during the soleus contractions FIG. 7B.The ankle dorsiflexion ROM (34°) is proportional to the adjacentplantarflexion ROM (33° and 34°). In the walking example of FIG. 7A,there is not a negative rotational movement or a minimal negativemovement between adjacent plantarflexions 502 in the single step. Insome instances, a negative X-axis movement may occur betweenplantarflexions 502 during walking. An additional step to determine if arotational movement, is an ankle dorsiflexion for the purposes herein,is to compare the negative rotational movement (velocity or angulardisplacement) to the adjacent plantarflexions. For example, if thenegative rotational movement is not proportional to the adjacentpositive rotational movements the negative rotational movement may bediscarded as being an ankle dorsiflexion. In an exemplaryimplementation, when the negative rotational movement is less than about50 percent of the absolute value of the positive rotational movements ofthe adjacent plantarflexions the negative rotational movement isdiscarded as an ankle dorsiflexion.

The disclosed systems can distinguish soleus contractions from othermovements with a single sensor 12 worn on the user's foot. Specifically,when a gyroscope is worn on the foot the soleus contraction movement iscategorically identified because of a motion that is primarily causingan ankle rotation that is lifting the heel toward the head/upper bodywhile the top of the foot is rotating such that it is starting to pointin an anterior direction in front of the body (“X-axis” of rotation isankle extension/flexion). With each soleus contraction, there is asingle ankle extension phase where the X-axis is generating measurableamounts of velocity and ROM. In contrast, during walking each step hastwo phases of ankle extension in the X-axis rotation, a smaller peak invelocity followed by a larger peak at the end of each stride rightbefore the toe is coming off the floor. Notice in FIG. 6A that theZ-axis is rotating during each step at the end of the stride, unlikewhat we see after the X-axis ankle extension of an SPU contraction.Although walking and house cleaning or manual labor do frequentlyinvolve ankle extension of greater than 3 degrees like a soleuscontraction, there is also often substantial rotation of the ankle inthe one or both of the other axes (distinguishable from soleuscontractions). For example, an ankle rotation may be discarded as asoleus contraction when either the Y-axis rotational movement or theZ-axis rotational movement exceed the X-axis rotational movement. Forsoleus contractions, the Y-axis and the Z-axis rotational movements donot approach the X-axis rotational movement. For example, during asoleus contraction the Y-axis and Z-axis will be less than about 80percent of the X-axis rotation. In another example, he Y-axis and Z-axiswill be less than about 50 percent of the X-axis rotation. In anotherexample, the Y-axis and Z-axis will be less than about 30 percent of theX-axis rotation.

An ankle rotation may be discarded as a soleus contraction when themedial rotation (Z-axis) and/or lateral rotation (Y-axis) concurrentwith the plantarflexion is greater than a limit, e.g., a rotation of1-degree, 2-degrees, 3-degrees, etc. A lateral or medial rotationallimit of about 5-degrees may be used to distinguish clean soleuscontractions from other random movements. However, the rotational limitcan be increased to provide a greater tolerance to account foranatomical variations from user to user. For example, a lateral ormedial angular displacement of about 12 degrees provides a largetolerance for anatomical variations.

There are other distinguishing features measured with the gyroscope thatcan differentiate soleus contractions that are feasible to include as anextra layer of analytical certainty. In addition to the ROM of the ankleand the angular velocity, the duration of a soleus contraction is oftenable to discern it from other types of movements. For example, there aresome movements like running, brisk walking, and jumping that can have aROM similar to good quality soleus contraction, but the peak angularvelocity is more than in soleus contractions. Rarely has a soleuscontraction greater than 300 degrees/sec been measured; yet walking at 3mph can approach 500 degrees/sec. Testing has shown that car driving isa common behavior with a low ROM of ankle movement caused by vibrationsof the road and is also distinguished by rapid series of movements intandem with a low velocity of each movement.

Examples of common activities that involve movement of the ankle, but ina motion that can be distinguished from soleus contractions with themethods disclosed include: walking, running, and jumping; house cleaning(kitchen work, putting away clothes, sweeping, etc.); manual labor(gardening, painting, construction, etc.); car riding (and other formsof vehicular transport like trains, planes, buses); sitting andfidgeting randomly; and sitting with a commonly performed rapid heeltapping motion that is too rapid.

The ROM of a plantarflexion is physiologically more important that therate of the performed soleus contractions. However, behaviorally peopleoften tend to think “faster is better,” and repetitions are easy tocount. People tend to perform plantarflexions faster than they shouldfor the purposes herein. However, a rate is not determinative if qualitysoleus contractions are achieved.

In an exemplary embodiment, a minimum range of motion for aplantarflexion to be identified as a soleus contraction is about 3degrees. However, a plantarflexion less than 3 degrees may qualify as asoleus contraction, although a low-quality soleus contraction.

FIG. 8 illustrates an exemplary method 800, operable by a processor of ameasurement unit, for monitoring plantarflexions. At block 802, a sensorlocated on a user's foot measures rotational movement about one or moreaxes aligned relative to the user's foot, where an X-axis extendslaterally relative to the foot, a Y-axis extends parallel to the foot,and a Z-axis extends orthogonal to the X-axis and the Y-axis and where apositive or first direction X-axis rotational movement corresponds tothe ankle angle increasing and the second direction X-axis rotationalmovement corresponding to the ankle angle decreasing. At block 804, apositive X-axis rotational movement is identified as a plantarflexionand a negative X-axis rotational movement is identified as an ankledorsiflexion. At block 806, the plantarflexion is deemed a performedsoleus contraction when the plantarflexion is immediately followed by anankle dorsiflexion for two consecutive cycles of plantarflexion andankle dorsiflexion. At block 808, information regarding the performedsoleus contractions is communicated.

FIG. 9 is a schematic illustration of an exemplary soleus contractionmonitoring unit or system 10. FIG. 9 is described with additionalreference in particular to FIGS. 1-3, 4C, and 8. Measurement unit 10includes a sensor 12 configured to measure rotational movement whenpositioned on a user's foot with an X-axis oriented laterally across thefoot, a Y-axis oriented parallel to the foot, and a Z-axis orthogonal tothe X-axis and the Y-axis. The sensor is arranged so that a positiveoutput or first direction X-axis rotation movement corresponds to aplantarflexion where the ankle angle increases. The rotational movementcan be measured, for example as angular velocity and/or angulardisplacement. Measurement system 10 includes a memory 16 (FIG. 1 )storing computer-executable instructions 18 (FIG. 1 ) for controlling aprocessor 14 to measure an X-axis rotational movement, identify apositive or first direction X-axis rotational movement as aplantarflexion and a negative or second X-axis rotational movement as adorsiflexion, deem the plantarflexion a performed soleus contractionwhen the plantarflexion is immediately followed by a dorsiflexion, andcause performance information regarding the performed soleuscontractions to be communicated. Utilizing a base 350 whereby the legsextend outward and the user cannot be walking, the soleus contractionscan be identified without criteria excluding walking characteristics.

Processor 14 is packaged with sensor 12 in the FIG. 9 embodiment. Sensor12 is packaged with a fastener 34 to secure the sensor to a user's foot300 (see, e.g., FIGS. 3 and 4C). Fastener 34 may comprise a loop andhook type feature, strap, sleeve, tie or other mechanism to secure thesensor on the user's foot. The fastener may attach directly to the footor via a sock or shoe.

A base 350 (e.g., base station) can aid the user in performing thedesired soleus contractions and in particular to performing qualitysoleus contractions. Base 350 includes a bottom surface 318 extendingalong a horizontal plane and a placement surface 320 extending upward,at an angle greater than zero, from the bottom surface for placement ofthe user's foot and a communication device 22 configured to communicatethe performance information. The placement surface may be parallel tothe bottom surface. In the illustrated embodiment, base 350 includes avisual communication device 22 a, an audible device 22 b, and an activetactile device 22 c. The measurement system may include one or morecommunication devices. The active tactile device 22 c may be a pad thatcommunicates selected performance information via physical stimulation,such as vibration, through the user's foot. For example, the activetactile device may communicate that the user is actuating performing theperformed soleus contractions.

The base 350 may take various shapes. The illustrated examples aretriangular; however, the base is not limited to a triangulararrangement. The placement surface 320 extends upward from the bottomsurface so that a user can place the forefoot on the placement surfacewith the heel able to move free of obstruction from the floor. Theplacement surface may be angled upward to facilitate placement of theuser with the ankle angle within a desired range and the user's legsextended outward.

Examples of performance information that may be communicated include therate of the performed soleus contractions, an average angulardisplacement of the performed soleus contractions over a time period,and a time duration the performed soleus contraction have beensubstantially continuously performed. Substantially continuouslyperformed can include intermittent breaks in the continuous performance,such as breaks that would account for interruptions in measurement data,time periods for adjustment of the user's feet, or other time periods.For example a substantially continuous performance of the soleuscontractions may include a time lapse of 30 seconds, one minute, twominutes, etc.

As used herein, the term “substantially,” “about,” “generally,” andsimilar terms are used as terms of approximation and not a terms ofdegrees, and are intended to account for the inherent deviations inmeasured and calculated values that would be recognized by a person ofskill in the art. Furthermore, as used herein, the terms “connect,”“connection,” “connected,” “in connection with,” and “connecting” may beused to mean in direct connection with or in connection with via one ormore elements. Similarly, the terms “couple,” “coupling,” and “coupled”may be used to mean directly coupled or coupled via one or moreelements.

The foregoing outlines features of several embodiments so that thoseskilled in the art may better understand the aspects of the disclosure.Those skilled in the art should appreciate that they may readily use thedisclosure as a basis for designing or modifying other processes andstructures for carrying out the same purposes and/or achieving the sameadvantages of the embodiments introduced herein. Those skilled in theart should also realize that such equivalent constructions do not departfrom the spirit and scope of the disclosure and that they may makevarious changes, substitutions, and alterations herein without departingfrom the spirit and scope of the disclosure. The scope of the inventionshould be determined only by the language of the claims that follow. Theterm “comprising” within the claims is intended to mean “including atleast” such that the recited listing of elements in a claim are an opengroup. The terms “a,” “an” and other singular terms are intended toinclude the plural forms thereof unless specifically excluded.

What is claimed is:
 1. A soleus contraction system to aide a user toproperly perform soleus push-ups, the system comprising: a base having abase surface extending along a horizontal plane and a placement surfaceextending upward from the base surface for positioning a foot of theuser on the placement surface with an ankle angle of about 60 to 80degrees when a heel and a forefoot are on the placement surface and thefoot is extended forward of a body of the user; a communication devicelocated on the base to visually, tactilely, and/or audibly communicateinformation to the user; a sensor configured to measure an angularvelocity of a rotational movement of the foot when positioned on thefoot, the sensor comprising a fastener configured to attach the sensorto the foot with an X-axis of the sensor oriented laterally across thefoot, a Y-axis oriented parallel to the foot, and a Z-axis orthogonal tothe X-axis and the Y-axis; a processor in communication with the sensor,the processor configured to receive the measurement of the angularvelocity of the rotational movement; and a memory storingcomputer-executable instructions for controlling the processor to:determine a duration and range of motion of an X-axis rotationalmovement; cause to be visually communicated in real time the duration ofthe X-axis rotational movement and at least one of the angular velocityor the range of motion of the X-axis rotational movement; identify apositive X-axis rotational movement as a plantarflexion; identify anegative X-axis rotational movement that immediately follows thepositive X-axis rotational movement as an ankle dorsiflexion if anabsolute value of the negative X-axis rotational movement is greaterthan about 50 percent of the positive X-axis rotational movement;designate the plantarflexion a soleus push-up when the plantarflexion isimmediately followed by the ankle dorsiflexion for two consecutivecycles of plantarflexion and ankle dorsiflexion and a duration of theplantarflexion is greater than about 80 msec; and cause performanceinformation regarding substantially continuous performance of aplurality of the soleus push-ups to be communicated by the communicationdevice during the substantially continuous performance wherein thecommunication device comprises a vibrating pad on the placement surface,the vibrating pad configured to communicate the performance informationvia physical stimulation to the foot.
 2. The system of claim 1, whereinthe communication device comprises a visual display.
 3. The system ofclaim 1, wherein the memory further stores computer-executableinstructions for controlling the processor to: determine a rate ofplantarflexions performed per minute; and exclude plantarflexions frombeing designated the plurality of the soleus push-ups when the rate isgreater than a rate limit, wherein the rate limit is one of: about 200per minute; about 250 per minute; and about 300 per minute.
 4. Thesystem of claim 1, wherein the memory stores computer-executableinstructions for controlling the processor to exclude the plantarflexionfrom being designated the soleus push-up when either a Y-axis rotationalmovement or a Z-axis rotational movement of the plantarflexion isgreater than the positive X-axis rotational movement of theplantarflexion.
 5. The system of claim 1, wherein the memory storescomputer-executable instructions for controlling the processor toexclude the plantarflexion from being designated the soleus push-up whenthe angular velocity is greater than about 300 degrees/sec.